U.S. patent number 9,321,936 [Application Number 13/773,723] was granted by the patent office on 2016-04-26 for addition curable silicone emulsion release composition and release film.
This patent grant is currently assigned to SHIN-ETSU CHEMICAL CO., LTD.. The grantee listed for this patent is Shin-Etsu Chemical Co., Ltd.. Invention is credited to Shinji Irifune, Tsutomu Nakajima, Kenji Yamamoto.
United States Patent |
9,321,936 |
Nakajima , et al. |
April 26, 2016 |
Addition curable silicone emulsion release composition and release
film
Abstract
An addition curable silicone emulsion release composition
suitable for forming a releasable film having a high releasability
to a pressure sensitive adhesives simultaneously with good adhesion
to a plastic film substrate is provided. A release film prepared by
coating and curing such composition on a plastic film is also
provided. The good adhesion and the high releasability to acryl
pressure sensitive adhesives are realized despite the low content
of the organopolysiloxane containing a large amount of
trifunctional siloxane units and alkenyl groups which had been used
for realizing the adhesion. The addition curable silicone emulsion
release composition is prepared by blending predetermined
proportion of mixtures of high molecular weight organopolysiloxanes
each containing an alkenyl group and phenyl group at particular
ratio.
Inventors: |
Nakajima; Tsutomu (Annaka,
JP), Irifune; Shinji (Annaka, JP),
Yamamoto; Kenji (Annaka, JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
Shin-Etsu Chemical Co., Ltd. |
Tokyo |
N/A |
JP |
|
|
Assignee: |
SHIN-ETSU CHEMICAL CO., LTD.
(Tokyo, JP)
|
Family
ID: |
47826901 |
Appl.
No.: |
13/773,723 |
Filed: |
February 22, 2013 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20130224502 A1 |
Aug 29, 2013 |
|
Foreign Application Priority Data
|
|
|
|
|
Feb 23, 2012 [JP] |
|
|
2012-036920 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C08L
83/04 (20130101); C09J 7/401 (20180101); C09D
183/04 (20130101); C09D 183/04 (20130101); C08L
83/00 (20130101); C08L 83/00 (20130101); C08L
83/00 (20130101); C08L 83/00 (20130101); C08K
5/56 (20130101); C09J 2483/005 (20130101); C08G
77/18 (20130101); C09J 2400/226 (20130101); C08G
77/20 (20130101); C08G 77/80 (20130101); C08G
77/12 (20130101); C08G 77/16 (20130101); Y10T
428/31663 (20150401) |
Current International
Class: |
C08J
3/03 (20060101); C09D 183/04 (20060101); C08L
83/04 (20060101); C08G 77/00 (20060101); C08G
77/12 (20060101); C08G 77/20 (20060101) |
Field of
Search: |
;428/447,41.4
;524/500,366,375,376 ;525/478,477 ;528/15,31,32 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
1 323 796 |
|
Jul 2003 |
|
EP |
|
1 557 451 |
|
Jul 2005 |
|
EP |
|
1 599 209 |
|
Sep 1981 |
|
GB |
|
54-52160 |
|
Apr 1979 |
|
JP |
|
57-53143 |
|
Nov 1982 |
|
JP |
|
63-314275 |
|
Dec 1988 |
|
JP |
|
6-57144 |
|
Mar 1994 |
|
JP |
|
11-222557 |
|
Aug 1999 |
|
JP |
|
3824072 |
|
Sep 2006 |
|
JP |
|
2009-263505 |
|
Aug 2009 |
|
JP |
|
2009-227976 |
|
Dec 2009 |
|
JP |
|
2009-227977 |
|
Dec 2009 |
|
JP |
|
2012-207125 |
|
Oct 2012 |
|
JP |
|
2012-207126 |
|
Oct 2012 |
|
JP |
|
WO 2012/132681 |
|
Oct 2012 |
|
WO |
|
WO 2012/132682 |
|
Oct 2012 |
|
WO |
|
Other References
Machine translation of JP 2012-207126, retrieved Sep. 18, 2015.
cited by examiner .
Machine translation of JP JP 2012-207125, retrieved Sep. 18, 2015.
cited by examiner .
Machine translation of JP 2009-227976, retrieved Sep. 18, 2015.
cited by examiner .
Machine translation of JP 2009-227977, retrieved Sep. 18, 2015.
cited by examiner .
Machine translation of JP 2009-263505, retrieved Sep. 18, 2015.
cited by examiner .
Extended Europeean Search Report issued Jun. 28, 2013, in European
Patent Application No. 13156230.8. cited by applicant.
|
Primary Examiner: Shosho; Callie
Assistant Examiner: Nelson; Michael B
Attorney, Agent or Firm: Birch, Stewart, Kolasch &
Birch, LLP
Claims
The invention claimed is:
1. An addition curable silicone emulsion release composition
comprising the following components (A) to (E): (A) 10 to 40 parts
by weight of an organopolysiloxane (I) having a viscosity at
25.degree. C. of 5 to 100 mPas represented by the following average
compositional formula (1): ##STR00008## wherein R.sup.1 is
independently an alkenyl group containing 2 to 8 carbon atoms;
R.sup.2 is independently a substituted or unsubstituted monovalent
hydrocarbon group containing 1 to 10 carbon atoms; R.sup.3 is
independently hydrogen atom or a substituted or unsubstituted
monovalent hydrocarbon group containing 1 to 10 carbon atoms and
not containing an aliphatic unsaturated bond; and letters a and b
are positive numbers and letter c is 0 or a positive number such
that (b+c)/a=0.6 to 1.5 and 0.ltoreq.c/(b+c).ltoreq.0.05; (B) 20 to
70 parts by weight of an organopolysiloxane (II) having a viscosity
at 25.degree. C. of 30 to 10,000 mPas represented by the following
average compositional formula (2): ##STR00009## wherein R.sup.4 is
independently a substituted or unsubstituted monovalent hydrocarbon
group containing 1 to 10 carbon atoms, with the proviso that at
least two R.sup.4 are an alkenyl group; and d and g are a positive
number and e and f are 0 or a positive number so that the viscosity
at 25.degree. C. is 30 to 10,000 mPas with the proviso that f is in
the range of 0.ltoreq.f.ltoreq.10; (C) 1 to 10 parts by weight of
an organopolysiloxane (III) having a number average molecular
weight of 100,000 to 900,000, and containing an alkenyl group with
an alkenyl value of at least 0.01 mol/100 g; (D) 5 to 30 parts by
weight of an organopolysiloxane (IV) having a number average
molecular weight in the range of 100,000 to 900,000, and having an
alkenyl group and an aryl group with an alkenyl value of at least
0.0002 mol/100 g and less than 0.01 mol/100 g, and an amount of the
aryl group in all organic groups of 0.5 to 10% by mol; content of
the component (A) being up to 40% by weight of the total content of
the component (A), the component (B), the component (C), and the
component (D), and a weight ratio, C/D, of the content of the
component (C) to the content of the component (D) is 1/9 to 5/5;
and (E) an organohydrogenpolysiloxane (V) having at least 3
hydrogen atoms directly bonded to silicon atoms per molecule, and
having a viscosity at 25.degree. C. is 5 to 2,000 mPas represented
by the following average compositional formula (3):
R.sup.5.sub.hH.sub.kSiO.sub.(4-h-k)/2 (3) wherein R.sup.5 is a
substituted or unsubstituted monovalent hydrocarbon group
containing 1 to 10 carbon atoms and not containing an aliphatic
unsaturated bond; and h and k are positive numbers satisfying
h+k.ltoreq.3; a molar ratio of the SiH group in the component (E)
to all alkenyl groups in the components (A) to (D) being 1.0 to
3.0.
2. The addition curable silicone emulsion release composition
according to claim 1 further comprising, in relation to 100 parts
by weight of the total of the components (A) to (E): (F) 0.1 to 20
parts by weight of a surfactant; (G) a catalytic amount of a
platinum group metal catalyst; and (H) 50 to 100,000 parts by
weight of water.
3. A release film produced by coating an addition curable silicone
emulsion release composition comprising the following components
(A) to (E): (A) 10 to 40 parts by weight of an organopolysiloxane
(I) having a viscosity at 25.degree. C. of 5 to 100 mPas
represented by the following average compositional formula (1):
##STR00010## wherein R.sup.1 is independently an alkenyl group
containing 2 to 8 carbon atoms; R.sup.2 is independently a
substituted or unsubstituted monovalent hydrocarbon group
containing 1 to 10 carbon atoms; R.sup.3 is independently hydrogen
atom or a substituted or unsubstituted monovalent hydrocarbon group
containing 1 to 10 carbon atoms and not containing an aliphatic
unsaturated bond; and letters a and b are positive numbers and
letter c is 0 or a positive number such that (b+c)/a=0.6 to 1.5 and
0.ltoreq.c/(b+c).ltoreq.0.05; (B) 20 to 70 parts by weight of an
organopolysiloxane (II) having a viscosity at 25.degree. C. of 30
to 10,000 mPas represented by the following average compositional
formula (2): ##STR00011## wherein R.sup.4 is independently a
substituted or unsubstituted monovalent hydrocarbon group
containing 1 to 10 carbon atoms, with the proviso that at least two
R.sup.4 are an alkenyl group; and d and g are a positive number and
e and f are 0 or a positive number so that the viscosity at
25.degree. C. is 30 to 10,000 mPas with the proviso that f is in
the range of 0.ltoreq.f.ltoreq.10; (C) 1 to 10 parts by weight of
an organopolysiloxane (III) having a number average molecular
weight of 100,000 to 900,000, and containing an alkenyl group with
an alkenyl value of at least 0.01 mol/100 g; (D) 5 to 30 parts by
weight of an organopolysiloxane (IV) having a number average
molecular weight in the range of 100,000 to 900,000, and having an
alkenyl group and an aryl group with an alkenyl value of at least
0.0002 mol/100 g and less than 0.01 mol/100 g, and an amount of the
aryl group in all organic groups of 0.5 to 10% by mol; content of
the component (A) being up to 40% by weight of the total content of
the component (A), the component (B), the component (C), and the
component (D), and a weight ratio, C/D, of the content of the
component (C) to the content of the component (D) is 1/9 to 5/5;
and (E) an organohydrogenpolysiloxane (V) having at least 3
hydrogen atoms directly bonded to silicon atoms per molecule, and
having a viscosity at 25.degree. C. is 5 to 2,000 mPas represented
by the following average compositional formula (3):
R.sup.5.sub.hH.sub.kSiO.sub.(4-h-k)/2 (3) wherein R.sup.5 is a
substituted or unsubstituted monovalent hydrocarbon group
containing 1 to 10 carbon atoms and not containing an aliphatic
unsaturated bond; and h and k are positive numbers satisfying
h+k.ltoreq.3; a molar ratio of the SiH group in the component (E)
to all alkenyl groups in the components (A) to (D) being 1.0 to 3.0
on a plastic film, and curing the coated composition.
4. The release film of claim 3, wherein said addition curable
silicone emulsion release composition further comprises, in
relation to 100 parts by weight of the total of the components (A)
to (E): (F) 0.1 to 20 parts by weight of a surfactant; (G) a
catalytic amount of a platinum group metal catalyst; and (H) 50 to
100,000 parts by weight of water.
Description
CROSS-REFERENCE TO RELATED APPLICATION
This non-provisional application claims priority under 35 U.S.C.
.sctn.119(a) on Patent Application No. 2012-036920 filed in Japan
on Feb. 23, 2012, the entire contents of which are hereby
incorporated by reference.
TECHNICAL FIELD
The present invention relates to an addition curable silicone
emulsion release composition suitable for use in forming a
releasable film exhibiting a high releasability to pressure
sensitive adhesives simultaneously with good adhesion to a plastic
film substrate. The present invention so relates to release film
prepared by coating and curing such composition on a plastic
film.
BACKGROUND ART
Various silicone compositions have been used for the release paper
which prevents sticking and bonding of the substrate such as paper
and plastics to a pressure-sensitive adhesive material. Of the
silicone compositions, solvent-type silicones have been widely used
in view of their release properties and relatively wide choice of
the substrate.
However, reduction in the amount of solvent used and recycling of
the solvent with no discharge into the exterior are recent demands
in view of environmental pollution, safety, hygiene, and the like.
With regard to the solvent reduction, use of a solventless silicone
is effective. However, homogeneous coating of such solventless
silicone on a substrate such as a paper, laminated paper, or
plastic film at a thickness of up to 1 .mu.m requires use of an
expensive coater and high skill, and change from a solvent-type
silicone to a solventless silicone is not generally employable.
Another effective method for reducing the solvent use is use of an
emulsion-type silicone. The silicones of such type are already
used, and exemplary such emulsion-type silicones include a mixture
of an emulsion comprising an organovinyl polysiloxane, a platinum
compound, an emulsifier, and water and an emulsion comprising an
organohydrogenpolysiloxane, an emulsifier, and water (JP-B
S57-53143), the one produced by emulsion polymerization (JP-A
S54-52160), and an organovinylsiloxane and an
organohydrogensiloxane which have been emulsified by using a
particular emulsifier, and which has been further mixed with an
emulsion of a platinum compound (JP-A S63-314275).
These emulsion-type silicones can be diluted with water to any
desired degree, and the expensive coater and high skill required in
the case of the solventless silicones are not required. Another
merit is similarity of the process with the solvent-type
silicone.
At present, however, the emulsion-type silicones are not widespread
because of the demerits that the dispersion medium is water. One
such demerit is the high latent heat of vaporization of the water
which inevitably results in the curing at a high temperature,
namely, lower curability compared to the solvent-type and the
solventless silicones. Another major demerit is the large surface
tension of the water which results in the inferior wettability of
the substrate, and hence, poor adhesion. These demerits are serious
particularly in the case of the plastic film substrate, and these
are the reason for the rare use of the emulsion-type silicones.
Many improvements have been proposed to solve the problems as
described above. Exemplary such improvements include use of an
organopolysiloxane having an alkenyl group at the terminal of the
molecule (JP-A H06-57144), and blending of an emulsion comprising a
non-silicone polymer (JP-A H11-222557). However, many of these
improvements are directed to paper substrates, and there has been
little or no proposal of the silicone emulsion which exhibits
satisfactory adhesion when the emulsion is coated on a plastic film
substrate.
In view of the situation as described above, the inventors of the
present invention made various investigations and reported that a
silicone emulsion composition mainly comprising an
organopolysiloxane wherein a trifunctional siloxane unit (T unit)
constitutes about 35 to 60% by mole in the entire siloxane units
and an alkenyl group constitutes at least 20% by mole in the entire
organic groups exhibits good adhesion to the plastic film substrate
(JP 3824072). While this composition exhibits good adhesion to
various plastic substrates, an organopolysiloxane containing a
large amount of trifunctional siloxane units and alkenyl groups
constituted at least 50% by weight of this composition as the
component realizing the adhesion, and it has been difficult to
realize a sufficiently high releasability to acryl
pressure-sensitive adhesives.
In the meanwhile, higher releasability tends to be required for the
release films used for a plastic film substrate such as those used
in optical applications and electronic and electric component
applications. However, there has been no silicone emulsion release
agent for plastic films which satisfied such demand.
SUMMARY OF INVENTION
Technical Problem
The present invention has been completed in view of the situation
as described above, and an object of the present invention is to
provide an addition curable silicone emulsion release composition
which is suitable for use in forming a releasable film exhibiting
releasability to pressure-sensitive adhesives simultaneously with
good adhesion to plastic film substrates. Another object of the
present invention is to provide a release film prepared by coating
such composition of a plastic film and curing the coated
composition.
Solution to Problem
In order to achieve the objects as described above, and more
specifically, in order to obtain a film which does not experience
loss of adhesion when content of the organopolysiloxane containing
a large amount of trifunctional siloxane units and alkenyl groups
added for realizing the adhesion is reduced and which exhibits high
releasability to acryl pressure sensitive adhesive, the inventors
of the present invention made an intensive investigation and found
that the silicone film prepared by curing the addition curable
silicone emulsion release composition containing the following
components as its main components, which has been prepared by
blending predetermined proportion of mixtures of high molecular
weight organopolysiloxanes each containing an alkenyl group and
phenyl group at particular ratio, exhibits sufficient adhesion to
the substrate as well as high releasability. The present invention
has been completed on the bases of such findings.
Accordingly, the present invention provides an addition curable
silicone emulsion release composition and a release film as
described below.
[1] An addition curable silicone emulsion release composition
comprising the following components (A) to (E):
(A) 10 to 40 parts by weight of an organopolysiloxane (I) having a
viscosity at 25.degree. C. of 5 to 100 mPas represented by the
following average compositional formula (1):
##STR00001## wherein R.sup.1 is independently an alkenyl group
containing 2 to 8 carbon atoms; R.sup.2 is independently a
substituted or unsubstituted monovalent hydrocarbon group
containing 1 to 10 carbon atoms; R.sup.3 is independently hydrogen
atom or a substituted or unsubstituted monovalent hydrocarbon group
containing 1 to 10 carbon atoms and not containing an aliphatic
unsaturated bond; and letters a and b are positive numbers and
letter c is 0 or a positive number such that (b+c)/a=0.6 to 1.5 and
0.ltoreq.c/(b+c).ltoreq.0.05;
(B) 20 to 70 parts by weight of an organopolysiloxane (II) having a
viscosity at 25.degree. C. of 30 to 10,000 mPas represented by the
following average compositional formula (2):
##STR00002## wherein R.sup.4 is independently a substituted or
unsubstituted monovalent hydrocarbon group containing 1 to 10
carbon atoms, with the proviso that at least two R.sup.4 are an
alkenyl group; and d and g are a positive number and e and f are 0
or a positive number so that viscosity at 25.degree. C. is 30 to
10,000 mPas with the proviso that f is in the range of
0.ltoreq.f.ltoreq.10;
(C) 1 to 10 parts by weight of an organopolysiloxane (III) having a
number average molecular weight of 100,000 to 900,000, and
containing an alkenyl group with alkenyl value of at least 0.01
mol/100 g;
(D) 5 to 30 parts by weight of an organopolysiloxane (IV) having a
number average molecular weight in the range of 100,000 to 900,000,
and having an alkenyl group and an aryl group with the alkenyl
value of at least 0.0002 mol/100 g and less than 0.01 mol/100 g,
and amount of the aryl group in all organic groups of 0.5 to 10% by
mol;
content of the component (A) being up to 40% by weight of the total
content of the component (A), the component (B), the component (C),
and the component (D), and content of the component (C) and the
component (D) being such that (C)/(D)=1/9 to 5/5 (weight ratio);
and
(E) an organohydrogenpolysiloxane (V) having at least 3 hydrogen
atoms directly bonded to silicon atoms per molecule, and having a
viscosity at 25.degree. C. is 5 to 2,000 mPas represented by the
following average compositional formula (3):
R.sup.5.sub.hH.sub.kSiO.sub.(4-h-k)/2 (3) wherein R.sup.5 is a
substituted or unsubstituted monovalent hydrocarbon group
containing 1 to 10 carbon atoms and not containing an aliphatic
unsaturated bond; and h and k are positive numbers satisfying
h+k.ltoreq.3;
molar ratio of the SiH group in the component (E) to all alkenyl
groups in the components (A) to (D) (amount of the SiH group/amount
of the alkenyl group) being 1.0 to 3.0.
[2] An addition curable silicone emulsion release composition
according to [1] further comprising
(F) 0.1 to 20 parts by weight of a surfactant;
(G) a catalytic amount of a platinum group metal catalyst; and
(H) 50 to 100,000 parts by weight of water in relation to 100 parts
by weight of the total of the components (A) to (E).
[3] A release film produced by coating the addition curable
silicone emulsion release composition of [1] or [2] on a plastic
film, and curing the coated composition.
Advantageous Effects of Invention
The addition curable silicone emulsion release composition of the
present invention realizes good adhesion to the film substrate
irrespective of the type of the plastic film substrate. In
addition, the cured film formed can be used as a release film since
it exhibits high releasability to pressure-sensitive adhesives.
DESCRIPTION OF EMBODIMENTS
Next, the present invention is described in detail.
The addition curable silicone emulsion release composition of the
present invention mainly comprises components (A) to (E) as
described below.
(A) an organopolysiloxane (I) having a viscosity at 25.degree. C.
is 5 to 100 mPas represented by the following average compositional
formula (1):
##STR00003## wherein R.sup.1 is independently an alkenyl group
containing 2 to 8 carbon atoms; R.sup.2 is independently a
substituted or unsubstituted monovalent hydrocarbon group
containing 1 to 10 carbon atoms; R.sup.3 is independently hydrogen
atom or a substituted or unsubstituted monovalent hydrocarbon group
containing 1 to 10 carbon atoms and not containing an aliphatic
unsaturated bond; and a and b are positive numbers and c is 0 or a
positive number such that (b+c)/a=0.6 to 1.5 and
0.ltoreq.c/(b+c).ltoreq.0.05.
(B) an organopolysiloxane (II) having a viscosity at 25.degree. C.
of 30 to 10,000 mPas represented by the following average
compositional formula (2):
##STR00004## wherein R.sup.4 is independently a substituted or
unsubstituted monovalent hydrocarbon group containing 1 to 10
carbon atoms, with the proviso that at least two R.sup.4 are an
alkenyl group; and d and g are a positive number and e and f are 0
or a positive number so that viscosity at 25.degree. C. is 30 to
10,000 mPas with the proviso that f is in the range of
0.ltoreq.f.ltoreq.10.
(C) an organopolysiloxane (III) having a number average molecular
weight of 100,000 to 900,000, and containing an alkenyl group with
alkenyl value of at least 0.01 mol/100 g.
(D) an organopolysiloxane (IV) having a number average molecular
weight in the range of 100,000 to 900,000, and having an alkenyl
group and an aryl group with the alkenyl value of at least 0.0002
mol/100 g and less than 0.01 mol/100 g, and amount of the aryl
group in all organic groups of 0.5 to 10% by mol.
(E) an organohydrogenpolysiloxane (V) having at least 3 hydrogen
atoms directly bonded to the silicon atom per molecule, and having
a viscosity at 25.degree. C. is 5 to 2,000 mPas represented by the
following average compositional formula (3):
R.sup.5.sub.hH.sub.kSiO.sub.(4-h-k)/2 (3) wherein R.sup.5 is a
substituted or unsubstituted monovalent hydrocarbon group
containing 1 to 10 carbon atoms and not containing an aliphatic
unsaturated bond; and h and k are positive numbers satisfying
h+k.ltoreq.3.
The organopolysiloxane (I) which is the component (A) constituting
the addition curable silicone emulsion release composition of the
present invention has a viscosity at 25.degree. C. of 5 to 100
mPas, and this organopolysiloxane (I) is represented by the
following average compositional formula (1):
##STR00005##
In the formula (1), R.sup.1 is an alkenyl group containing 2 to 8
carbon atoms such as vinyl group, allyl group, butenyl group, and
pentenyl group. Preferably, R.sup.1 is vinyl group.
R.sup.2 is independently a substituted or unsubstituted monovalent
hydrocarbon group containing 1 to 10 carbon atoms, and in
particular, 1 to 6 carbon atoms selected from alkyl groups such as
methyl group, ethyl group, propyl group, and butyl group,
cycloalkyl groups such as cyclohexyl group, alkenyl groups such as
vinyl group, allyl group, butenyl group, and pentenyl group, aryl
groups such as phenyl group and tolyl group, and any one of such
groups having a part or all of the hydrogen atoms bonded to the
carbon atom substituted with hydroxyl group, cyano group, or a
halogen atom such as hydroxypropyl group, cyanoethyl group,
1-chloropropyl group, and 3,3,3-trifluoropropyl group; and R.sup.2
is preferably methyl group or vinyl group. R.sup.1 and R.sup.2 may
be the same of different.
R.sup.3 is hydrogen atom or a substituted or unsubstituted
monovalent hydrocarbon group not containing an aliphatic
unsaturated bond and containing 1 to 10 carbon atoms, and in
particular, 1 to 6 carbon atoms selected from alkyl groups such as
methyl group, ethyl group, propyl group, and butyl group,
cycloalkyl groups such as cyclohexyl group, aryl groups such as
phenyl group and tolyl group, and any one of such groups having a
part or all of the hydrogen atoms bonded to the carbon atom
substituted with hydroxyl group, cyano group, or a halogen atom
such as hydroxypropyl group, cyanoethyl group, 1-chloropropyl
group, and 3,3,3-trifluoropropyl group; and R.sup.3 is preferably
methyl group.
In industrial point of view, the alkenyl group of the
organopolysiloxane (I) is preferably vinyl group. Amount of the
alkenyl group in the organopolysiloxane (I) is preferably an amount
such that its alkenyl value is 0.50 to 0.65 mol/100 g, and in
particular 0.53 to 0.62 mol/100 g.
Letters a and b are independently a positive number and letter c is
0 or a positive number. Preferably, letter a is a positive number
of 0<a.ltoreq.50, letter b is a positive number of
0<b.ltoreq.50, and letter c is 0.ltoreq.c.ltoreq.5.
Ratio (b+c)/a is in the range of 0.6 to 1.5, and preferably 0.8 to
1.3. Ratio (b+c)/a of less than 0.6 will result in the loss of the
adhesion to the plastic film substrate which is characteristic to
the present invention, while ratio (b+c)/a in excess of 1.5 will
result in the unduly increased content of the R.sup.2SiO.sub.3/2
and the R.sup.2(R.sup.3O)SiO.sub.2/2 which in turn results in the
difficulty of synthesizing the organopolysiloxane (I). Ratio
c/(b+c) is in the range of 0 to 0.05, and preferably 0 to 0.03.
Ratio c/(b+c) in excess of 0.05 will result in the excessive
content of the alkoxy group or the hydroxy group, which in turn
results in the poor curability of the silicone emulsion release
composition.
The viscosity at 25.degree. C. of the organopolysiloxane (I) is in
the range of 5 to 100 mPas, and preferably 20 to 80 mPas. When the
viscosity is less than 5 mPas, the resulting silicone emulsion
release composition will have a poor storage stability while
viscosity in excess of 100 mPas will result in the difficulty of
synthesizing the organopolysiloxane (I). In the present invention,
the viscosity may be measured by using a rotary viscometer.
The organopolysiloxane (I) may also contain a monofunctional
siloxane unit, a difunctional siloxane unit, or a tetrafunctional
siloxane unit not having an alkenyl group at an amount not
adversely affecting the merits of the present invention.
The component (A) may be incorporated at an amount in the range of
10 to 40 parts by weight in relation to 100 parts by weight of the
total of the components (A) to (D), and the content is preferably
in the range of 10 to 30 parts by weight in order to realize the
sufficient adhesion simultaneously with the easy release. In order
to realize the easy release, content of the component (A) should be
up to 40% by weight of the components (A) to (D). Excessively low
content of the component (A) results in the poor adhesion.
Next, the organopolysiloxane (II) of the component (B) has a
viscosity at 25.degree. C. of 30 to 10,000 mPas, and this
organopolysiloxane (II) is represented by the following average
compositional formula (2):
##STR00006##
In the formula (2), R.sup.4 is independently a substituted or
unsubstituted monovalent hydrocarbon group containing 1 to 10
carbon atoms, and in particular, 1 to 6 carbon atoms selected from
alkyl groups such as methyl group, ethyl group, propyl group, and
butyl group, cycloalkyl groups such as cyclohexyl group, alkenyl
groups such as vinyl group, allyl group, butenyl group, and
pentenyl group, aryl groups such as phenyl group and tolyl group,
and any one of such groups having a part or all of the hydrogen
atoms bonded to the carbon atom substituted with hydroxyl group,
cyano group, or a halogen atom such as hydroxypropyl group,
cyanoethyl group, 1-chloropropyl group, and 3,3,3-trifluoropropyl
group. At least 2, and preferably 2 to 6 of the R.sup.4 are an
alkenyl group. R.sup.4 is preferably methyl group or vinyl
group.
In the organopolysiloxane (II), amount of the alkenyl group is
preferably an amount such that its alkenyl value is 0.003 to 0.1
mol/100 g, and in particular, 0.005 to 0.05 mol/100 g.
The viscosity at 25.degree. C. of the organopolysiloxane (II) is in
the range of 30 to 10,000 mPas, and preferably 50 to 500 mPas. When
the viscosity is less than 30 mPas, the silicone emulsion release
composition will have poor storage stability, while sufficiently
cured film will not be obtained at the viscosity in excess of
10,000 mPas. Letter f is in the range of 0.ltoreq.f.ltoreq.10, and
preferably 0 to 3, and d, e, and g are not particularly limited,
and may be selected so that the organopolysiloxane (II) has the
viscosity in the range as described above. The organopolysiloxane
(II) wherein f is in excess of 10 will be gelated during the
synthesis, and production of such organopolysiloxane (II) will be
difficult.
The organopolysiloxane (II) is the component which has a large
effect on the releasability of the silicone emulsion release
composition of the present invention. Release properties of the
cured film of the silicone emulsion release composition can be
adjusted by changing structure and substituents of the
organopolysiloxane (II). The organopolysiloxane (II) may not
necessarily comprise single component, and it may be a mixture of
several organopolysiloxanes each having different compositions as
long as the average compositional formula of the components
satisfies the requirements as described above.
The component (B) may be incorporated at an amount in the range of
20 to 70 parts by weight, and preferably, at 30 to 60 parts by
weight in relation to 100 parts by weight of the total of the
components (A) to (D). Curability will be insufficient and
reliability will also be insufficient when the content of the
component (B) is excessively low while excessive incorporation will
result in the insufficient adhesion to the film substrate.
Next, the organopolysiloxane (III) of the component (C) has a
number average molecular weight of 100,000 to 900,000, and this
contains an alkenyl group without fail, and the alkenyl value is at
least 0.01 mol/100 g.
The alkenyl group may be selected from those containing 2 to 8
carbon atoms such as vinyl group, allyl group, butenyl group, and
pentenyl group. Industrially preferable alkenyl group is vinyl
group.
The alkenyl value is at least 0.01 mol/100 g, and preferably at
least 0.02 mol/100 g. The alkenyl value of less than 0.01 mol/100 g
will result in the loss of adhesion. The alkenyl value is
preferably at least 0.1 mol/100 g.
The monovalent group directly bonded to the silicon atom other than
the alkenyl group are not particularly limited, and examples
include substituted or unsubstituted monovalent hydrocarbon groups
containing 1 to 10 carbon atoms, and in particular, 1 to 6 carbon
atoms selected from alkyl groups such as methyl group, ethyl group,
propyl group, and butyl group, cycloalkyl groups such as cyclohexyl
group, aryl croups such as phenyl group and tolyl group, and any
one of such groups having a part or all of the hydrogen atoms
bonded to the carbon atom substituted with hydroxyl group, cyano
group, or a halogen atom such as hydroxypropyl group, cyanoethyl
group, 1-chloropropyl group, and 3,3,3-trifluoropropyl group. Among
these, the preferred is methyl group.
The organopolysiloxane (III) is not particularly limited for its
molecular structure, while it may preferably have a straight chain
molecular structure. The number average molecular weight is in the
range of 100,000 to 900,000, and preferably 200,000 to 700,000. The
number average molecular weight of less than 100,000 results in the
reduced adhesion while the number average molecular weight in
excess of 900,000 results in poor stability of the emulsion.
The number average molecular weight used in the present invention
is the number average molecular weight measured by gel permeation
chromatography (GPC) conducted under the conditions as described
below using polystyrene as standard substance.
[Measurement Conditions] Developing solvent: toluene Flow rate:
0.35 ml/min. Detector: differential refractive index detector (RI)
Column: product name, TOSOH SuperHZ 4000, SuperHZ 3000, SuperHZ
2000 (manufactured by Tosoh) Column temperature: 40.degree. C.
Amount of the sample added: 20 .mu.L (toluene solution at a
concentration of 0.5% by weight)
The component (C) may be used at an amount in the range of 1 to 10
parts by weight, and preferably 3 to 10 parts by weight in relation
to the total of the to components (A) to (D). Excessively low
amount of the component (C) results in poor adhesion while
excessive use also results in the poor adhesion.
The organopolysiloxane (IV) of the component (D) has a number
average molecular weight in the range of 100,000 to 900,000, and
this organopolysiloxane (IV) has an alkenyl group and an aryl group
without fail, and the alkenyl value is at least 0.0002 mol/100 g
and less than 0.01 mol/100 g, and amount of the aryl group is 0.5
to 10% by mol of all organic groups.
The alkenyl group used is the one containing 2 to 8 carbon atoms
such as vinyl group, allyl group, butenyl group, and pentenyl
group, and the preferred is vinyl group in industrial point of
view.
The alkenyl value is at least 0.0002 mol/100 g and less than 0.01
mol/100 g, preferably at least 0.001 mol/100 g and less than 0.01
mol/100 g, and more preferably 0.0015 to 0.005 mol/100 g. The value
of less than 0.0002 mol/100 g will result in poor curability while
the value of 0.01 mol/100 g or more will result in poor
adhesion.
The aryl group used may be the one containing 6 to 12 carbon atoms
such as phenyl group and tolyl group, and the preferred is phenyl
group in industrial point of view.
Content of the aryl group is such that amount of the aryl group in
the entire organic group is 0.5 to 10% by mol, and preferably 1 to
3% by mol. The amount of the aryl group of less than 0.5% by mol or
more than 10% by mol will result in poor adhesion.
The monovalent group other than the alkenyl group and the aryl
group directly bonded to silicon atom is not particularly limited,
and examples include a substituted or unsubstituted monovalent
hydrocarbon group containing 1 to 10 carbon atoms, and in
particular, 1 to 6 carbon atoms excluding the alkenyl groups and
the aryl groups such as alkyl groups such as methyl group, ethyl
group, propyl group, and butyl group, cycloalkyl groups such as
cyclohexyl group, and any of such groups having a part of all of
the hydrogen atoms bonded to the carbon atom substituted with
hydroxyl group, cyano group, halogen atom, or the like such as
hydroxypropyl group, cyanoethyl group, 1-chloropropyl group, and
3,3,3-trifluoropropyl group. Among these, the preferred is methyl
group.
The organopolysiloxane (IV) is not particularly limited for its
molecular structure, while it may preferably have a straight chain
molecular structure. The number average molecular weight is in the
range of 100,000 to 900,000, and preferably 200,000 to 700,000. The
number average molecular weight of less than 100,000 results in the
reduced adhesion while the number average molecular weight in
excess of 900,000 results in poor stability of the emulsion.
The component (D) may be used at an amount in the range of 5 to 30
parts by weight, and preferably 7 to 25 parts by weight in relation
to 100 parts by weight of the total of the components (A) to (D).
Excessively low amount of the component (D) results in poor
adhesion while excessive use also results in the poor adhesion.
In the present invention, the adhesion is greatly influenced by the
weight ratio of the component (C) to the component (D), and it is
important that (C)/(D) is 1/9 to 5/5 (weight ratio). The weight
ratio (C)/(D) is more preferably 2/8 to 4/6. Sufficient adhesion is
not realized then the ratio (C)/(D) is less than 1/9 or greater
than 5/5.
The organopolysiloxane (V) of the component (E) is the
organopolysiloxane represented by the following average
compositional formula (3): R.sup.5.sub.hH.sub.kSiO.sub.(4-h-k)/2
(3) wherein at least 3 hydrogen atoms are directly bonded to the
silicon atom per molecule, and this organopolysiloxane (V) has a
viscosity at 25.degree. C. of 5 to 2,000 mPas.
In the formula (3), R.sup.5 is a substituted or unsubstituted
monovalent hydrocarbon containing 1 to 10 carbon atoms, and in
particular, 1 to 6 carbon atoms not containing an aliphatic
unsaturated bond selected from alkyl groups such as methyl group,
ethyl group, propyl group, and butyl group, cycloalkyl groups such
as cyclohexyl group, aryl groups such as phenyl group and tolyl
group, and any of such groups having a part or all of the hydrogen
atoms bonded to the carbon atom substituted with hydroxyl group,
cyano group, halogen atom, or the like such as hydroxypropyl group,
cyanoethyl group, 1-chloropropyl group, and 3,3,3-trifluoropropyl
group. Rc is preferably methyl group or ethyl group.
Letters h and k are positive numbers satisfying h+k.ltoreq.3.
Preferably, h is a positive number of 0<h.ltoreq.2, k is a
positive number of 0<k.ltoreq.1, and h+k is a positive number of
2 to 3.
The organohydrogenpolysiloxane (V) is an organohydrogenpolysiloxane
having at least 3, and preferably 3 to 100 hydrogen atoms directly
bonded to silicon atoms per molecule, and the amount of the SiH
group is 0.2 to 1.6 mol/100 g, and preferably 1 to 1.6 mol/100
g.
The organohydrogenpolysiloxane (V) is incorporated at an amount
such that molar ratio of the SiH group in the component (E) to all
alkenyl groups in the components (A) to (D) (amount of the SiH
group/amount of the alkenyl group) is 1.0 to 3.0, and more
preferably, 1.2 to 2.0. When this ratio is less than 1.0,
curability will be greatly reduced while the ratio in excess of 3.0
will result in excessively increased release force.
The addition curable silicone emulsion release composition of the
present invention preferably further comprises
(F) a surfactant,
(G) a platinum group metal catalyst, and
(H) water.
Examples of the surfactant (F) include nonionic surfactants such as
alkylether surfactants such as polyoxyethylene laurylether and
polyoxyethylene tridecylether, and alkyl ester surfactants such as
polyoxyethylene oleate and polyoxyethylene laurate, and these
nonionic emulsifiers may be used alone or in combination of two or
more. In view of producing a stable silicone emulsion release
composition, HLB of the nonionic emulsifier or its mixture is
preferably 10 to 15.
An anionic surfactant or a cationic surfactant may also be used.
However, such surfactant is preferably used in combination with a
nonionic surfactant in view of the stability of the silicone
emulsion and wettability in the application to the substrate.
The surfactant is preferably used at the minimum amount required to
realize sufficient stability of the silicone emulsion and substrate
wettability. More specifically, the surfactant is preferably used
at an amount of 0.1 to 20 parts by weight, and more preferably 0.5
to 15 parts by weight in relation to 100 parts by weight of the
total of the components (A) to (E). Use at an amount of less than
0.1 parts by weight may result in the difficulty of the
emulsification while use at an amount in excess of 20 parts by
weight may result in poor curability of the silicone emulsion.
A water-soluble resin may be used in combination with the
surfactant to improve emulsification and stability of the resulting
emulsion. Exemplary water-soluble resins include polyvinyl alcohol,
and the water-soluble resin selected should be the one exhibiting
least catalyst poisoning to the platinum group metal catalyst. The
water-soluble resin is preferably used at the minimum amount
required to realize sufficient stability of the silicone emulsion
and substrate wettability as in the case of the surfactant. More
specifically, the water-soluble resin is preferably used at an
amount of 0.1 to 20 parts by weight, and more preferably 1 to 10
parts by weight in relation to 100 parts by weight of the total of
the components (A) to (E).
The platinum group metal catalyst (G) is a catalyst used for
promoting the addition reaction, and any known addition catalyst
may be used for this purpose. Examples of the platinum group metal
catalyst include catalysts such as platinum, palladium, and rhodium
catalysts, and among these, the preferred are platinum catalysts
such as chloroplatinic acid, alcohol solution or aldehyde solution
of chloroplatinic acid, and complex of chloroplatinic acid with
various olefin or vinyl siloxane.
The platinum group metal catalyst may be used at a catalytic
amount, and preferably, at an amount of the platinum group metal of
1 to 1,000 ppm in relation to 100 parts by weight of the total of
the components (A) to (E) in order to obtain good cured film and in
economic point of view.
Preferably, the platinum group metal catalyst (G) is not emulsified
simultaneously with other components, and the platinum group metal
catalyst (G) may be added immediately before the use of the
emulsion after preparing the emulsion of the components (A) to (E).
The platinum group metal catalyst is preferably prepared in water
dispersible form before its addition, for example, by preliminarily
mixing with a surfactant.
The silicone emulsion release composition of the present invention
may be prepared by a method known in the art. For example, the
silicone emulsion release composition may be prepared by mixing the
predetermined amount of the components (A) to (G) and a part of the
water (H) by using a high shearing agitator such as planetary mixer
or combi-mixer, emulsifying the mixture by phase transfer method,
adding residual part of the water (H), and diluting the emulsion.
Each of these components may comprise single or two or more
components.
Amount of the water (H) is not particularly limited as long as
viscosity suitable for the coater actually used in the coating and
desired coating weight of the composition on the substrate are
realized. The amount used is preferably 50 to 100,000 parts by
weight, and in particular, 100 to 10,000 parts by weight in
relation to 100 parts by weight of the total of the components (A)
to (E) (the organopolysiloxanes (I) to (V)). At less than 50 parts
by weight, production of an O/W-type emulsion will be difficult,
and the stability will be poor at the amount in excess of 100,000
parts by weight.
The water used is not particularly limited as long as the impurity
in the water is at the level of tap water. Use of water
contaminated with strong acid, strong alkali, large concentration
alcohol, salts, or the like is unsuitable for use since the
resulting emulsion suffers from poor stability.
In addition to the components as described above, the composition
may also include other optional components, for example, a
catalytic inactivator such as an organic nitrogen compound, organic
phosphor compound, acetylene derivative, oxime compound, or organic
halide for suppressing catalytic activity of the platinum group
metal catalyst; silicone resin, silica, or an organopolysiloxane
not containing hydrogen atom or an alkenyl group bonded to the
silicon atom for controlling releasability; a leveling agent such
as fluorine-based surfactant; or a thickening agent such as
water-soluble polymer, for example, methylcellulose. Such optional
components may be added at an amount commonly used in the art not
inhibiting the merits of the present invention.
The thus prepared silicone emulsion release composition may be used
as a release film by coating on a substrate which is most
preferably a plastic film, and heat curing. Examples of the plastic
film used include polyolefin films such as biaxially stretched
polypropylene film, polyethylene film, and ethylene-propylene
copolymer film, and polyester films such as polyethylene
terephthalate film. The film substrate is not particularly limited
for its thickness. However, the substrate may typically have a
thickness of about 5 to 100 .mu.m.
The silicone emulsion release composition of the present invention
may be coated on the substrate by using gravure coater, air knife
coater, roll coater, wire bar, or the like to a non-limited coating
weight, which is typically about 0.1 to 2.0 g/m.sup.2 in terms of
the solid content of the silicone emulsion release composition
(about 0.1 to 2.0 .mu.m in thickness).
When the silicone emulsion release composition of the present
invention is coated on the substrate, and heated at 80.degree. C.
to 160.degree. C. for about 5 seconds to 3 minutes, for example, in
a hot air circulation dryer, a cured film of the silicone emulsion
release composition is formed on the substrate and the film will be
releasable. Alternatively, the film may be cured by exposing to
infrared or ultraviolet beam, or by using these method in
combination to thereby improve curing efficiency.
As described above, use of the addition curable silicone emulsion
release composition of the present invention enables production of
a releasable plastic film which exhibits good adhesion to a plastic
film substrate simultaneously with high releasability to various
pressure sensitive adhesives.
EXAMPLES
Next, the present invention is described in further detail by
referring to Examples and Comparative Examples which by no means
limit the scope of the present invention. It is to be noted that
parts and % in the following Examples and Comparative Examples are
parts by weight and % by weight, and physical properties in the
Tables are the measurements obtained by the following test
procedures.
[Curability]
The silicone emulsion release composition immediately after the
preparation was coated on a 38 .mu.m PET (polyethylene
terephthalate) film substrate to a cured silicone coating weight of
0.3 g/m.sup.2, and dried in a hot air drier at 120.degree. C. for a
predetermined time. The resulting cured film was rubbed several
times with finger, and the film was visually examined for haze and
peeling. The curability is indicated by the time (second) required
for the curing.
[Adhesion]
The silicone emulsion release composition immediately after the
preparation was coated on a 38 .mu.m PET film substrate to a cured
silicone coating weight of 0.3 g/m.sup.2, and dried in a hot air
drier at 120.degree. C. for 30 seconds. The resulting cured film
was stored at room temperature for 1 day, and then rubbed several
times with finger. The film was visually examined for haze and
peeling (initial adhesion). This release film was also stored in a
thermostat bath oven at 50.degree. C. for 14 days, and the cured
film was rubbed several times with finger and the film was visually
examined for haze and peeling (prolonged adhesion).
[Release Force]
The silicone emulsion release composition immediately after the
preparation was cured at 120.degree. C. for 30 seconds by the same
procedure as the measurement of the curability to prepare a release
film. An acryl pressure-sensitive adhesive BPS-5127 (manufactured
by Toyo Ink Mfg. Co., Ltd.) was coated on the release surface of
the release film, and heated at 100.degree. C. for 3 minutes. Next,
the same release film was adhered to this coated surface, and the
sample was cut at a width of 5 cm. After aging at room temperature
for 1 day, the film was peeled off the laminate on a tensile tester
at an angle of 180.degree. at a peeling speed of 0.3 m/min, and the
force (N/5 cm) required for the release was measured.
[Residual Adhesion]
A cured film of the silicone emulsion release composition was
formed as in the case of the release force measurement, and a
polyester tape No. 31B (manufactured by Nitto Denko Corporation)
was adhered to its surface. A load of 1,976 Pa was placed on the
tape, and the laminate was heated at 70.degree. C. for 20 hours.
The tape was peeled, and then adhered to a stainless steel plate.
The tape was then peeled off the stainless steel plate, and the
force (N/5 cm) required for the peeling was measured. Percentage of
this force in relation to the force required for peeling a
non-treated standard tape was calculated (residual adhesion).
Silicone Emulsion 1
A 5-L combined emulsifier equipped with an anchor stirrer capable
of stirring the entire vessel and a rotating disc having
alternately upward and downward raised small teeth arranged along
its circumference (T.K. CombiMix Model M manufactured by Primix
Corp.) was charged with 200 parts of an organopolysiloxane (a)
having a viscosity at 25.degree. C. of 30 mPas and a vinyl group
content of 0.60 mol/100 g represented by the following average
compositional formula:
##STR00007## (the organopolysiloxane (I) of component (A)); 550
parts of a straight chain dimethylpolysiloxane (b) containing vinyl
group at opposite ends having a viscosity of 400 mPas and a vinyl
group content of 0.02 mol/100 g (the organopolysiloxane (II) of
component (B)); 50 parts of a dimethylpolysiloxane (c) containing
vinyl group at its end and in the side chain having a number
average molecular weight of about 400,000, and containing vinyl
group as the alkenyl group with the vinyl value of 0.04 mol/100 g
to (the organopolysiloxane (III) of component (C)); 200 parts of a
vinyl group- and phenyl group-containing dimethylpolysiloxane (d)
containing vinyl group as the alkenyl group at its end and in the
side chain with the vinyl value of 0.002 mol/100 g and phenyl group
as the aryl group with the amount of the phenyl group of 1.5% by
mol in relation to the total organic groups, having a number
average molecular weight of about 400,000 (the organopolysiloxane
(IV) of component (D)); 150 parts of methylhydrogenpolysiloxane (e)
having a viscosity at 25.degree. C. of 40 mPas and SiH group
content of 1.2 mol/100 g (the organohydrogenpolysiloxane (V) of
component (E)); 23 parts of polyoxyethylene laurylether having an
HLB of 13.6 (the surfactant (f) of component (F); 1,150 parts of
10% aqueous solution of polyvinyl alcohol (the thickener); and 5
parts of ethynylcyclohexanol (the catalytic activity suppressor);
and the mixture was homogeneously agitated. To this mixture, 150
parts of water was added for phase transfer, and the stirring was
continued for another 30 minutes. This emulsion was transferred to
a 15-L tank having an agitator, and after adding 9,047 parts of
water for dilution and stirring, an O/W emulsion 1 having a
silicone content of 10% was obtained. Silicone Emulsion 2
The procedure of preparing the silicone emulsion 1 was repeated
except that 350 parts of the organopolysiloxane (a) as the
component (A); 550 parts of the dimethylpolysiloxane (b) containing
vinyl group at opposite ends as the component (B); 10 parts of the
dimethylpolysiloxane (c) containing vinyl group at its end and in
the side chain as the component (C); 200 parts of the vinyl group-
and phenyl group-containing dimethylpolysiloxane (d) as the
component (D); 250 parts of the methylhydrogenpolysiloxane (e) as
the component (E); and 25 parts of the surfactant (f) as the
component (F) were used; and after adding 9,920 parts of water for
dilution was added. After the stirring, an O/W emulsion 2 having a
silicone content of 10% was obtained.
Silicone Emulsion 3
The procedure of preparing the silicone emulsion 1 was repeated
except that 500 parts of the organopolysiloxane (a) as the
component (A); 350 parts of the dimethylpolysiloxane (b) containing
vinyl group at opposite ends as the component (B); 50 parts of the
dimethylpolysiloxane (c) containing vinyl group at its end and in
the side chain as the component (C); 100 parts of the vinyl group-
and phenyl group-containing dimethylpolysiloxane (d) as the
component (D); 350 parts of the methylhydrogenpolysiloxane (e) as
the component (E); and 27 parts of the surfactant (f) as the
component (F) were used; and 10,818 parts of water for dilution was
added. After the stirring, an O/W emulsion 3 having a silicone
content of 10% was obtained.
Silicone Emulsion 4
The procedure of preparing the silicone emulsion 1 was repeated
except that 200 parts of the organopolysiloxane (a) as the
component (A); 650 parts of the dimethylpolysiloxane (b) containing
vinyl group at opposite ends as the component (B); 100 parts of the
dimethylpolysiloxane (c) containing vinyl group at its end and in
the side chain as the component (C); 50 parts of the vinyl group-
and phenyl group-containing dimethylpolysiloxane (d) as the
component (D); 150 parts of the methylhydrogenpolysiloxane (e) as
the component (E); and 23 parts of the surfactant (f) as the
component (F) were used; and 9,047 parts of water for dilution was
added. After the stirring, an O/W emulsion 4 having a silicone
content of 10% was obtained.
Silicone Emulsion 5
The procedure of preparing the silicone emulsion 1 was repeated
except that 500 parts of the organopolysiloxane (a) as the
component (A); 500 parts of the dimethylpolysiloxane (b) containing
vinyl group at opposite ends as the component (B); no components
corresponding to the components (C) and (D); 150 parts of the
methylhydrogenpolysiloxane (e) as the component (E); and 27 parts
of the surfactant (f) as the component (F) were used; and 10,818
parts of water for dilution was added. After the stirring, an O/W
emulsion 5 having a silicone content of 10% was obtained.
Silicone Emulsion 6
The procedure of preparing the silicone emulsion 1 was repeated
except that 200 parts of the organopolysiloxane (a) as the
component (A); 600 parts of the dimethylpolysiloxane (b) containing
vinyl group at opposite ends as the component (B); no component
corresponding to the component (C); 200 parts of the vinyl group-
and phenyl group-containing dimethylpolysiloxane (d) as the
component (D); 150 parts of the methylhydrogenpolysiloxane (e) as
the component (E); and 23 parts of the surfactant (f) as the
component (F) were used; and after adding 9,047 parts of water for
dilution was added. After the stirring, an O/W emulsion 6 having a
silicone content of 10% was obtained.
Example 1
100 parts of the silicone emulsion 1 was blended with 1.5 parts of
platinum catalyst emulsion CAT-PM-10A manufactured Shin-Etsu
Chemical Co., Ltd., and the blend was thoroughly mixed for use as
the silicone emulsion release composition. The composition was
measured for its curability, adhesion, release force, and residual
adhesion. The results are shown in Table 2.
Example 2
The procedure of Example 1 was repeated except that silicone
emulsion 2 was used instead of the silicone emulsion 1. The
composition was measured for its curability, adhesion, release
force, and residual adhesion. The results are shown in Table 2.
Comparative Example 1
The procedure of Example 1 was repeated except that silicone
emulsion 3 was used instead of the silicone emulsion 1. The
composition was measured for its curability, adhesion, release
force, and residual adhesion. The results are shown in Table 2.
Comparative Example 2
The procedure of Example 1 was repeated except that silicone
emulsion 4 was used instead of the silicone emulsion 1. The
composition was measured for its curability, adhesion, release
force, and residual adhesion. The results are shown in Table 2.
Comparative Example 3
The procedure of Example 1 was repeated except that silicone
emulsion 5 was used instead of the silicone emulsion 1. The
composition was measured for its curability, adhesion, release
force, and residual adhesion. The results are shown in Table 2.
Comparative Example 4
The procedure of Example 1 was repeated except that silicone
emulsion 6 was used instead of the silicone emulsion 1. The
composition was measured for its curability, adhesion, release
force, and residual adhesion. The results are shown in Table 2.
TABLE-US-00001 TABLE 1 List of the composition of Examples and
Comparative Examples Example Comparative Example Component Unit 1 2
1 2 3 4 (A) The component (a) Part by 20 35 50 20 50 20
corresponding to weight organopolysiloxane (I) (B) The component
(b) Part by 55 35 35 65 50 60 corresponding to weight
organopolysiloxane (II) (C) The component (c) Part by 5 10 5 10 0 0
corresponding to weight organopolysiloxane (III) (D) The component
(d) Part by 20 20 10 5 0 20 corresponding to weight
organopolysiloxane (IV) (E) The component (e) Part by 15 25 35 15
35 15 corresponding to weight organohydrogenpolysiloxane (V)
(A)/((A) + (B) + (C) + (D)) .times. 100 % by 20 35 50 20 50 20
weight (C)/(D) Weight 0.25 0.5 0.5 2.0 -- -- ratio Total amount of
SiH group in Molar 1.8 1.8 1.8 1.8 1.8 1.8 (E)/total amount of
alkenyl ratio group in (A) to (D) The component (f) corresponding
Part by 2 2 2 2 2 2 to the surfactant weight *1 The component
corresponding to Part by 1,023 1,111 1,200 1,023 1,200 1,023 water
weight *2 *1: Part by weight in relation to 100 parts by weight of
(A) + (B) + (C) + (D) + (E) *2: Part by weight in relation to 100
parts by weight of (A) + (B) + (C) + (D) + (E)
TABLE-US-00002 TABLE 2 Release properties in Examples and
Comparative Examples Example Comparative Example Item measured 1 2
1 2 3 4 Curability (sec) 30 25 30 30 30 30 Initial adhesion *1 A A
A C A C Prolonged adhesion *1 A A A C A C Release force (N/5 cm)
0.15 0.20 0.60 0.18 0.70 0.15 Residual adhesion (%) 95 97 95 95 95
95 *1: The adhesion was evaluated A when the film was in good
condition with no haze and peeling, B when slight haze was noted,
and C when peeling was observed.
Examples 1 and 2 demonstrate that the silicone emulsion release
composition of the present invention exhibits good adhesion to the
film substrate and high releasability.
Comparative Examples 1 and 3 demonstrate that the release force is
increased when the content of the organopolysiloxane component (I)
is 50% by weight or higher in the organopolysiloxane components (I)
to (IV).
Examples 1 and 2 and Comparative Examples 2 and 4 demonstrate that
the strong adhesion is realized simultaneously with the high
releasability when the components (C) and (D) of the present
invention are incorporated at a particular ratio.
INDUSTRIAL APPLICABILITY
This invention is useful in the field of release papers.
Japanese Patent Application No. 2012-036920 is incorporated herein
by reference.
Although some preferred embodiments have been described, many
modifications and variations may be made thereto in light of the
above teachings. It is therefore to be understood that the
invention may be practiced otherwise than as specifically described
without departing from the scope of the appended claims.
* * * * *